Tracing table



July 10,1928.

l M. G. JACKSON TRACING TABLE 2 Sheets-Sheet 1 Filed Feb. 14, 1927 July1o,192s. A 1,676,440.

4 M. G. JACKSON TRACING TABLE Filed Feb. 14, 1927 2 sheets-sheet 2 Patented July 10, 19,28.

Uru'rlnl STATES MARY G. JACKSON, OF NEWAHAVEN, CONNECTICUT.

'rimonta TABLE.

Application led February 14, 1927. Serial No. 167,933.

This invention relates to improvement in tracing tables, and particularly to tracing tables provided with translumlnescent surfaces to facilitate tracing through relatively opaque paper. The object of this invention 'is to provide a superior tracing table of the class described. constructed with particular reference to being simple and self-contained.

With this object in view, my invention consists in a tracing table-having certain details of construction and combinations of parts as will be hereinafter described and particularly recited in the claims.

In the accompanying drawings:

Fig. 1 is a top or plan view of a tracing table constructed in accordance with my invention;

Fig. 2 is a side view thereof;

Fig. 3` is a transverse sectional view on the line 33 of Fig. 1 and Fi 4 is al longitudinal sectional view on the line 4-4 of Fig. 2.

My improved tracing table, as herein shown, is particularly adapted for draftsmens use, but has a Wide range of use in other fields without departing from my invention.

In carrying out my I employ a sloping table-top 5 mounted upon four legs 6 which are provided with endlbraces 7 and a back-brace 8. The table-.top aforesaid is provided with a rectangular opening 9 for the reception of a verticallymovable box-like casing 10 which snugly vfits it.

The top of the casing just mentioned is formed by a rectangular sheet of glass 11 or other transparent material mounted in a narrow frame 12 of soft wood, so as to adapt it t0 readily receive thumbtacks or other fastening means for securing the paper in place over the glass. Parallel with and spaced slightly above the bottom 13 of-'the casing 10, so as to form a chamber 14, is a partition 15, the top surface of which is painted or otherwise treated to afford a reflecting and diffusing surface for thewlight emanating from a group of incandescent bulbs 16 whichare located above it and beneath the glass 11 aforesaid.

The chamber 14, just described, serves to house the socket 17 from which the bulbs 16 upstan'd, and the wires 18, which ,supply them with current under the control of a rheostat 19 of any approved tfype. This rheostat is secured to the under ace of the invention, as shown,

- surface, are

bottom 13 of the casing and is furnished with the usual control handle 20.

' At the opposite ends of the rectangular opening 9 of the table-top 5 I locate two corresponding depending brackets 21 and which are secured to its under surface by screws 23. Each-of these brackets is formed on its inner face with a vertical guide-groove 24 for the reception of a guide-rib 25 secured to the opposite ends respectively of the casing l() aforesaid for the guidance of the latter in its vertical movement, which is effected by means of a cylindrical eccentric bar 26 adapted to engage cleats 27 secured to the bottom 13 and which is provided with offset trunnions 28' and 29 at its opposite ends.

These trunnions have bearing 1n the adjacent brackets 21 and 2'2v respectively. The trunnion 28 is provided upon its projecting outer end with a hand-wheel 30, by means of which they eccentric bar 26 may be turned so as to raise and lower the casing 10 with the effect of projecting the top faces of the glass 11 and frame 12 above the surface of the table-top 5, as shown in Fig 3, or of retiring them into the plane thereof, as shown in Fig-'4.

. Preferably and as shown, casing 10 is curved inward as at 31 to provide clearance for the knees of the user when seated.

By my invention, therefore, the transluminescent tracing-surface may be raised above the level of the table-top 5, so as to provide a convenient edge for the guidance of a `T-square or, on the other hand, .when itis desired to employ' the entire area of the table-top, the' tracing-surface may be lowered so as to lie in the same plane and virtually constitute part of its surface.

Furthermore, by providing variable illumination, I am enabled to regulate the light vso as to accommodate its strength to the character of the work to be done, as I have found that the character of the lines to be traced, the color, opacity and thickness of the papersuperimposed upon the tracingfactorsl which must be taken into account in determining the strength of li ht required to avoid blurring and to obtain the best results.

I claim:

1. As a new article of manufacture, a tracing table com rising a. table-top, supports therefor, a bod y-movable rectangular transluminescent traoingaurface of less length the front of the and breadth than the said table and adapted to set therein, and means' for raising the said surface above the table-top and retiring it to the plane thereof.

2. As a new artlcle of manufacture, a tracing table comprising a table-top, supports therefor, an opening formed in the said table-top, a vertically-movable rectangular.

y ports therefor, an opening formed ,in the said table-top, guide-brackets adjacent the opposite ends of the said opening, a vertically-movable rectangular casing installed in the said opening, guides formed on the said casin for engagement with the said guidebrac ets, a transparent top for the said casing, electric lights mounted therein, and means for raising the said transparent to of the casin above the surface of the sald table-top an for-retiring it to -the plane thereof.

4. As a new article of manufacture, a tracing table comprising a table-top, supports therefor,'an opening formed in the said table-top, a vertically-movable rectangular casing installed in the said opening, a transparent top for,the said casing, electric lights mounted therein, an eccentric bar extending from endto end of said table for raising the said transparent top of the casing above the surface of the said table-top and for retiring it to the plane thereof.

In testimony whereof, I have signed this specification. i

MARY G. JACKSON. 

